The invention relates generally to ion laser structures and more particularly to ion laser structures which include an electromagnet and which are water cooled.
Ion lasers generally comprise a plasma tube and separate optical resonator. The plasma tube contains the gain medium, a plasma created by running a discharge between an anode and cathode mounted at opposite ends of the tube. The optical resonator is the structure which supports a pair of spaced aligned mirrors positioned around the gain medium to produce lasing action. The plasma tube and optical resonator are generally two separate structures, with the plasma tube contained within the resonator by complex mounting arrangements. It would be highly advantageous and desirable to simplify the resonator-plasma tube structure in an ion laser to reduce the number of parts, make the design more compact, increase serviceability and reliability, and reduce costs, and increase performance.
In operation, a CW ion laser generates a lot of heat, which must be removed, at least in certain applications where stability of laser output is critical. The heat can cause thermal expansion of the resonator structure which will affect the mirror alignment and thus the laser output. Changes in cavity length result in frequency detuning of the laser. Thus, it is highly advantageous and desirable to provide water cooling in an ion laser. Water cooling of the laser is frequently utilized.
By magnetically compressing the plasma in an ion laser tube, higher gain and higher efficiency are obtained. Most water cooled ion lasers include a solenoid electromagnet around the plasma tube. Since the electromagnet also generates heat, it can be water cooled. However, as previously described, the plasma tube and resonator are separate structures so the inclusion of a water cooled electromagnet makes the total structure even more complex. Thus, it is also highly advantageous and desirable to simplify the design of an ion laser with a water cooled electromagnet.
To be most effective, the water cooling of the laser resonator must be uniform. If uneven cooling between the top and bottom of the resonator is provided, e.g., if the flow channels are not uniform, then the temperature difference between the top and bottom of the resonator may be sufficient to bend the resonator significantly, misaligning the mirrors and changing the laser output, even preventing lasing. This problem can be reduced by providing a thermal short between the top and bottom of the resonator. Shields or thermally conducting elements mounted in the resonator have been utilized, but these add components and are not totally effective. However, it would be advantageous and desirable to provide a top to bottom thermal short in the resonator.
Accordingly, it is an object of the invention to provide an improved design for a plasma tube--optical resonator configuration in an ion laser.
It is also an object of the inventor to provide a simplified structure for an ion laser.
It is another object of the invention to provide an ion laser structure including an electromagnet for compressing the plasma in the laser tube.
It is a further object of the invention to provide a water cooled laser structure which more effectively cools the resonator, electromagnet and plasma tube.
It is yet another object of the invention to provide a top to bottom thermal short in an ion laser resonator.
It is another object to minimize environmental effects to an ion laser resonator.